An apparatus of this type, for dewatering fluids, is disclosed WO 2010/042663 A2. In this known apparatus, a further control valve is disposed at the end of the shared line opposite the control valve, which connects the shared line to the fluid inlet of the dewatering chamber when in a first setting and to the fluid reservoir when in a second setting. A supply line is formed for fluid that is to be dewatered when the two control valves are in the respective first setting, which fluid can flow from the fluid reservoir via the shared line to the fluid inlet of the dewatering chamber. By switching the two control valves to the respective second settings, a discharge for at least partially dewatered fluid is formed, which discharge can flow from the fluid outlet of the dewatering chamber via the shared line to the fluid reservoir. The alternating assignment of the shared line to the supply and to the discharge enables a construction and an operation of the apparatus with a single fluid pump disposed in the shared line. Further fluid pumps are unnecessary, such that, on the whole, a simpler structure of the apparatus is ensured, having a reduced weight and structural size.